Programming in the 1960s

NICTA Copyright 2012 From imagination to impact

Programming in

the 1960s: a

Personal History

Len Bass


I graduated college with a Bachelor’s degree

in Mathematics in 1964

• Two possible positions

– Actuary

– Computer programmer

• Guess which one I took?

• Prior computer experience

– Saw a computer once on a tour

– No knowledge of programming

• I was given a thin book on Fortran II and told to learn it.

• First program was copied out of the book. It didn’t work

because the machine I used it on ran Fortran IV.

2


Job workflow - submission

• Type up submission on cards

• Place job card with submission number in front

of cards

• Give cards to operator


Fortran IBM card


026 Keypunch


Operator loads cards into card reader


IBM 7094 processes job

7


IBM Chain Printer prints output


Final portion of the workflow

• Operator takes cards and output, places them

into a box with submission number in front and

places box in wooden frame

• Elapsed time ~2-3 hours, typically.


First Assignment – involved Legendre

Polynomials

• The formula involved computing N! / M!

• It took me six weeks to debug with much wasted

computer time.

• Why? 7! overflowed when computed as an

integer on a 36 bit word.

• Recall I had a degree in mathematics

– Factorials were integers.

– Who ever heard of “overflow”

10


Consequence

• Debriefing meeting with my boss and my boss’

boss.

• Outcome – my boss should have overseen me

more closely.

• It wasn’t my fault!! It was management’s fault.

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1968 – I am off to graduate school at Purdue

• Purdue constructed new mathematical

sciences/computer sciences building

– Completed in 1967

– Designed for IBM 360/67 in basement


IBM 360/67 was ~3 years late

• Purdue replaced their order with a CDC 6600


Why is this interesting?

• Mathematical Sciences building was designed to

have an IBM 360/67 in the basement

• Building was constructed with an external

elevator shaft to take computer to the basement

• CDC 6600 was two inches wider than the IBM

360/67

• Had to redig the elevator shaft!!


My assistantship

• Systems programmer for the High Energy

Physics department

• They had an IBM 360/44. What we would today

call a RISC machine


IBM 360/44


I learn to boot the machine

• I was shown how to boot the IBM 360/44

– Push blue button on lower right

– Enter date/time on console

• First time I did this …


• Lights went out

• Bells went off

• There was a power failure at that moment


IBM repairman as terrorist

• IBM performed weekly preventive maintenance

where card dust is vacuumed from inside the

computer.

• Involves removing the front panel of the console

• Purdue installed intrusion alarms on all of the

computers on campus including the High Energy

Physics computer

• The intrusion alarm prevented the repairman

from removing the front panel.

• So … he removed the intrusion alarm


Consequences

• Removing the intrusion alarm set off a silent

alarm at the campus police state

• Policemen in full riot gear and shotguns arrived

at the computer.

• …

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Me ~1980


The world has changed!!

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Software

Programming in the 1960s